How does rotation and scale affect a point lamp?
It doesn't - rotation and scale have no effect on a point light.

A point light emits light uniformly in all directions, so rotating it does nothing.  Note that if you change the lamp to any other type (Sun, Spot, Hemi, or Area) rotation will affect the direction of the light.



Scale also has no effect on the output of the lamp.  This can be demonstrated by trying to apply the scale of the lamp wth Ctrl+A, which will throw an error: Objects have no data to transform.

Note that if you change the lamp to an Area lamp, scale will affect the size of the lamp.  Scaling a Hemi lamp to very small values has a strange result, it seems to take much longer to render and produce drastically more noise on the first few samples, but not really change the actual lighting pattern.